Abstract:Reports a theory which explains the flickering motion of turbulent plumes as well as their large-scale sinuous structure. The theory is based on the fact that the inviscid region of the plume (the `plume column') possesses elastic properties analogous to those of elastic rods subjected to longitudinal compression. It is shown that the straight plume column is not stable and buckles. The distance between two consecutive elbows is proportional to the local plume diameter, in other words, the shapes of all buckled plumes are generally similar. A buckled plume collapses periodically due to the interaction of its lateral elbows with the stagnant ambient. This interaction is responsible for the intermittent formation of large-scale buoyant eddies on the periphery of the turbulent plume